1. Field of the Invention
The present invention relates to bulk containers for flowable materials and, more specifically, to a flexible bulk container system which allows for the more complete evacuation of a viscous material from a container.
2. Description of the Prior Art
It is known in the art when moving viscous material, such as grease and the like, to utilize a container having a rigid exterior frame and a flexible interior pocket. Typically the interior pocket contains a top mounted inlet and a side mounted drain. The pocket is filled from the top inlet, which is capped for transportation and storage. When it is desired to evacuate the container, the drain is opened and the material is allowed to flow out of the container through the drain.
When dealing with viscous materials such as grease, especially when the grease is cooled and thereby less flowable, it is desirable to provide a mechanism for forcing the grease from the container through the drain.
It is known in the art to provide a two-ply pocket having an inner pocket coupled to an outer pocket, such as that shown in U.S. Pat. Nos. 6,427,873 and 6,234,351, both of which are incorporated herein by reference. In such a construction, the inner pocket is welded or otherwise secured to the outer pocket along the exterior seams. The inner pocket and outer pocket are also welded to one another along one perpendicular line behind the inlet, and across another perpendicular line below the drain. The outer pocket is provided with a hose which allows for the pumping of air into the inner stice between the inner pocket and the outer pocket. As air is pumped into the inner stice, the air biases the inner pocket away from the outer pocket. The welds prevent the air from causing the inner pocket to cover a portion of the drain, thereby stemming the flow of material therethrough.
While such prior art constructions aid in the evacuation of viscous material such as grease and the like, such prior art pockets have certain drawbacks. One drawback associated with such prior art devices is that the straight weld between the inner pocket and outer pocket positioned below the drain frustrates complete evacuation of the flowable material from the portion of the pocket where the weld meets the edges of the inner pocket and outer pocket. An additional drawback associated with such prior art devices is that the failure of the system to more completely evacuate the flowable material at the points where the weld below the drain meets the edges of the inner pocket and outer pocket leads to the evacuation process taking an undesirably long time. Additionally, as most prior art evacuation systems are provided with a system for providing a vacuum around the drain, the additional time required to attempt to evacuate the flowable material leads to the increased likelihood that the pressure on the inner pocket will force a portion of the inner pocket across the drain opening, thereby stalling or at least substantially slowing the evacuation of the system. The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention.